Ms Findon`s findings concerning the antibody response to avian infectious bronchitis (IB) reported in this issue of the New Zealand Veterinary Journal have improved our knowledge about the use of the vaccine prepared from the New Zealand “A” strain of virus (Poulvac) in layers. When I developed this vaccine at Massey University in the mid-seventies, financial support came exclusively from a large broiler company and from a pharmaceutical company, so that research centred on the needs of the broiler industry and in particular the search for a mild strain giving cross-protection against the four serotypes of IB virus known to occur in New Zealand in those years. Duration of immunity was of less relevance because of the short life-span of broilers other than parent stock. Ms Findon`s results prove what had to be expected…